In a large saucepan, add potatoes and turnips and add just enough cold water to cover them. Bring to a boil for 12-15 minutes, until you can easily insert a fork into the chunks. You want them to be soft, but not falling apart. Drain potatoes and set aside.

Mash the potato mixture with a masher or a whisk, breaking up large chunks. Mash to your desired level of smoothness. I like mine chunky, more smashed than mashed. Continue to cook potatoes, on medium-low for another 5 to 7 minutes, stirring frequently.